A difficult diagnosis

Mr Mahon's case1 shows the importance of carrying out investigations on the kidney in patients who have a recently diagnosed varicocele. Although Mr Mahon did not have occlusion of his renal vein, ultrasonography of the abdomen showed a previously undiagnosed abdominal aortic aneurysm that needed repair, renal cysts, and a solid renal lesion. Oncocytoma is difficult to …

Mr Mahon's case 1 reminded me of two general matters. Firstly, vascular surgeons need to maintain good communications with urologist colleagues. Over the years, urologists have been a good source of referrals, going as far back as the days when a plain abdominal radiograph would unexpectedly show a calcified abdominal aortic aneurysm during a search for a renal stone or in a patient with acute urinary retention.
Secondly, we must continue to argue on behalf of patients for a national ultrasonographic screening service for abdominal aortic aneurysms. Vascular surgeons and our national societies, here and abroad, have long campaigned for this, and if our advocacy had been more persuasive, Mr Mahon's aneurysm would have been detected at a smaller and much more easily treatable size. In the event, he was lucky that his 8 cm aneurysm was successfully repaired before it ruptured. An additional benefit of screening is that virtually all aneurysms would be diagnosed before they ruptured, eliminating the need for sometimes long and complicated surgical repairs in patients with poor prognosis in the middle of the night. This would help patients as well as delighting vascular surgeons and their long suffering families.

Surgical risks
Turning to the specifics of Mr Mahon's case, the first point is the high priority of surgical repair before rupture occurs. Last year, the National Confidential Enquiry into Patient Outcome and Death reported that patients spent too long waiting for this procedure. 2 Careful preoperative assessment is required. Anaesthetists say that vascular patients are among the sickest patients they look after. An intensive care bed must be available, and the lack of these beds causes too many elective repairs to be cancelled at the last minute. This major surgery should not take place unless all essential elements of the care package are available.
What operative mortality risk should be disclosed? Hadjianastassiou and colleagues reported a crude mortality of 9.3% for 1205 patients admitted to intensive therapy units in North East Thames after elective repair of an abdominal aortic aneurysm during 1992 to 2000. 3 The British National Vascular Database reported a mortality of 7.3% after repair of 797 unruptured aneurysms in 2003. 4 Mr Mahon's risk was around 10% bearing in mind his age, the size of his aneurysm, and his comorbidities.
Should Mr Mahon have been advised to have this major operation, with the appreciable risks involved and his life expectancy further compromised by the renal tumour? 5 Speaking generally, most patients whose life expectancy is more than a year feel the operation is worthwhile to free them from the threat of death from a ruptured aneurysm.

Sanjiv Agarwal
Mr Mahon's case 1 shows the importance of carrying out investigations on the kidney in patients who have a recently diagnosed varicocele. Although Mr Mahon did not have occlusion of his renal vein, ultrasonography of the abdomen showed a previously undiagnosed abdominal aortic aneurysm that needed repair, renal cysts, and a solid renal lesion. Oncocytoma is difficult to diagnose before surgery. The classic features are a central stellate scar on computed tomography and a spoke wheel pattern of feeding arteries on angiography, but these findings are unreliable and of poor predictive value. 2 The stellate features were not obvious in Mr Mahon's contrast enhanced computed tomogram, making a radiological diagnosis more difficult. Characteristics for oncocytoma on magnetic resonance imaging include a well defined capsule, a central stellate scar, and distinctive intensities on T1 and T2 images. Although these features all suggest the diagnosis, they should not be considered definitive. 3 Diagnosis from a renal biopsy aspirate also presents problems. It is difficult to distinguish oncocytoma from the granular forms of conventional renal cell carcinoma or the eosinophilic variant of chromophobe cell carcinoma. 4 In addition, renal cell carcinoma and oncocytoma have been reported to coexist in the same lesion or location of the kidney in 7% to 32% of cases. 5 Given these uncertainties about a pre-operative diagnosis, most surgeons would treat these tumours aggressively with exploration and repairing surgery or radical nephrectomy depending on the clinical circumstance. 5 A nephron sparing approach is clearly desirable if oncocytoma is suspected and if tumour size and location are amenable. However, as Mr Mahon's surgeon thought that a partial nephrectomy was totally impossible, the decision to postpone the left nephrectomy to a later date was appropriate.

Commentary: Interactivity and case learning
Ed Peile The volume of online response to this interactive case report has been disappointing. 1 This prompted me to reflect on the nature of interactivity in online learning and in learning in general. Learners' engagement with, and participation in, educational learning activities is widely accepted to enhance their learning. There is also evidence that in group activities, learning for peers is enhanced by participation of others. So if interactivity is beneficial, how do we encourage this participation, be it with published cases, with material on a website, or in live lectures, ward rounds, or clinic teaching?
A starting point is to consider the nature of interaction. In this series, for example, we have seen doctors engaging cognitively at several levels (box). Informal discussion suggests that for each person who files a rapid response, many more engage with the material and reflect on it but do not interact publicly. There may be many reasons for this, ranging from reticence and fear of appearing stupid to lack of time or opportunity. There is scope for research here, as cases that prompt a large volume of response seem to show much active learning, and your comments would be welcome.

Relevance
But what do we know about encouraging interactivity of relevance to every clinician who teaches? Obvious prerequisites include making the situation unthreatening and being responsive to learners' input, but there are some more subtle features about the cases we use in learning. Whether we are teaching around (and hopefully with) the patient or describing the patient's case to the learner, authenticity is more than just being based on a real event in a real patient's life. Research suggests that authentic case based approaches in education improve learning not only because of their relevance to the real world but because they contain ill defined, problematic elements with competing solutions and diversity of outcome, which prompt reflection and hopefully collaboration with others. 2 Such learning has application outside the specific domain.
In this context it is worth remembering the words of Etienne Wenger: "Learning cannot be designed; it can only be designed-for: that is facilitated or frustrated." 3 Competing interests: None declared.